constant.hpp

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#ifndef _TERRY_GENERATOR_CONSTANT_HPP_
#define _TERRY_GENERATOR_CONSTANT_HPP_

#include <boost/gil/utilities.hpp>

#include <cmath>

namespace terry {
namespace generator {

// Models a Unary Function
template <typename P>
// Models PixelValueConcept
struct ConstantFunctor
{
        typedef boost::gil::point2<double>    point_t;
        typedef ConstantFunctor const_t;
        typedef P value_type;
        typedef value_type reference;
        typedef value_type const_reference;
        typedef point_t argument_type;
        typedef reference result_type;
        BOOST_STATIC_CONSTANT( bool, is_mutable = false );

        value_type _color;

        ConstantFunctor() {}
        ConstantFunctor( const value_type& color )
                : _color( color )
        {
        }

        result_type operator()( const point_t& ) const
        {
                return _color;
        }

};


template <typename Pixel>
struct ConstantColorViewFactory
{
        typedef terry::generator::ConstantFunctor<Pixel> ConstantFunctorT;
        typedef typename ConstantFunctorT::point_t Point;
        typedef boost::gil::virtual_2d_locator<ConstantFunctorT, false> Locator;
        typedef boost::gil::image_view<Locator> ConstantVirtualView;
        
        static ConstantVirtualView getView( const Pixel& color )
        {
                boost::function_requires<PixelLocatorConcept<Locator> >();
                gil_function_requires < StepIteratorConcept<typename Locator::x_iterator> >();

                return ConstantVirtualView( Point( 1, 1 ), Locator( Point( 0, 0 ), Point( 1, 1 ), ConstantFunctorT( color ) ) );
        }
};

template <typename Pixel>
typename ConstantColorViewFactory<Pixel>::ConstantVirtualView constantColorView( const Pixel& color )
{
        return ConstantColorViewFactory<Pixel>::getView( color );
}
        

}
}

#endif